1. Scope of Invention
This invention relates generally to a fuel system supply, and more particularly to a liquid propane reserve system for use in conjunction with industrial vehicles powered by liquid propane.
2. Prior Art
Liquid propane is commonly used in industrial equipment installations due to the cleaner burning benefits achieved during internal combustion engine operation of such industrial equipment in enclosed areas such as those found in a warehouse or manufacturing facility. Liquid propane is also used in many residential and commercial installations for both heating and operating of commercial equipment such as stoves and refrigerators.
In many of these installations, determining the amount of liquid propane remaining in such storage tanks is quite difficult to determine. Moreover, when such tanks are disconnected for refilling and the tank still contains a useful amount of liquid propane, the propane refilling company will normally charge the user the full amount of the capacity of the tank with no credit given for any useful amounts of remaining propane in the tank.
As a result, much of the commercial equipment dependent upon liquid propane is operated until the tank is fully emptied. In the case of any such commercial equipment such as a forklift truck, the operator is then forced to retrieve a fresh tank of liquid propane before continuing with the work tasks at hand. This represents a significant delay in every day commercial productivity.
Sims, in U.S. Pat. No. 5,704,387 discloses a propane reserve tank which is intended to address this very problem particularly focusing on forklift trucks and other inside use industrial vehicles where liquid propane is the fuel of choice for environmental cleanliness. Sims does teach a propane reserve system including a reserve tank which automatically functions to open the filled reserve tank when the pressure level in the main tank drops to a preselected level. However, the Sims fuel control network between the engine, the main tank and the reserve tank is quite complex and may not represent a reliable or economically viable answer to this long-felt need in this industry. Moreover, there is no assurance that the main tank will be emptied before the reserve tank is automatically engaged.
The present invention provides a system including a reserve tank system which is extremely simple in nature and one which is manually operated by the vehicle or equipment operator to insure reliability in an economical fashion and without the need for removal of the reserve tank for refilling which may be yet another drawback to the Sims' system.